From d83018e9be719e5434d9daac3061b180da3aa5e1 Mon Sep 17 00:00:00 2001
From: James Higgins <james.isaac.higgins@gmail.com>
Date: Sun, 18 Apr 2021 16:31:15 -0300
Subject: [PATCH 1/2] Add Overflow::Hidden for Nodes

---
 crates/bevy_ui/src/flex/mod.rs    | 54 +++++++++++++++++++++++++++++--
 crates/bevy_ui/src/lib.rs         |  7 ++++
 crates/bevy_ui/src/render/ui.frag | 11 +++++--
 crates/bevy_ui/src/render/ui.vert |  7 ++++
 crates/bevy_ui/src/ui_node.rs     | 18 ++++++++++-
 examples/ui/ui.rs                 |  1 +
 6 files changed, 91 insertions(+), 7 deletions(-)

diff --git a/crates/bevy_ui/src/flex/mod.rs b/crates/bevy_ui/src/flex/mod.rs
index 2b89351211cc9..ec3788c69fb4c 100644
--- a/crates/bevy_ui/src/flex/mod.rs
+++ b/crates/bevy_ui/src/flex/mod.rs
@@ -1,15 +1,16 @@
 mod convert;
 
-use crate::{CalculatedSize, Node, Style};
+use crate::{CalculatedSize, Node, Overflow, Style};
 use bevy_app::EventReader;
+use bevy_ecs::system::QuerySet;
 use bevy_ecs::{
     entity::Entity,
     query::{Changed, FilterFetch, With, Without, WorldQuery},
     system::{Query, Res, ResMut},
 };
 use bevy_log::warn;
-use bevy_math::Vec2;
-use bevy_transform::prelude::{Children, Parent, Transform};
+use bevy_math::{Vec2, Vec3, Vec4};
+use bevy_transform::prelude::{Children, GlobalTransform, Parent, Transform};
 use bevy_utils::HashMap;
 use bevy_window::{Window, WindowId, WindowScaleFactorChanged, Windows};
 use std::fmt;
@@ -187,6 +188,53 @@ pub enum FlexError {
 unsafe impl Send for FlexSurface {}
 unsafe impl Sync for FlexSurface {}
 
+pub fn bounds_node_system(
+    windows: Res<Windows>,
+    mut query_set: QuerySet<(
+        Query<(Option<&Parent>, &Style, &Node, &GlobalTransform)>,
+        Query<&mut Node>,
+    )>,
+    query: Query<Entity, With<Node>>,
+) {
+    // y gets flipped somewhere..
+    let window = windows.get_primary().unwrap();
+    let window_height = window.height();
+    let get_bounds = |position: Vec3, size: Vec2| -> Vec4 {
+        Vec4::new(
+            position.x - size.x / 2.0,
+            window_height - (position.y + size.y / 2.0),
+            position.x + size.x / 2.0,
+            window_height - (position.y - size.y / 2.0),
+        )
+    };
+    for entity in query.iter() {
+        let mut current_entity = entity;
+        let mut bounds = Default::default();
+        loop {
+            if let Ok((parent, style, node, global_transform)) = query_set.q0().get(current_entity)
+            {
+                if current_entity == entity {
+                    bounds = get_bounds(global_transform.translation, node.size);
+                }
+                if style.overflow == Overflow::Hidden {
+                    bounds = get_bounds(global_transform.translation, node.size);
+                    break;
+                }
+                if let Some(parent) = parent {
+                    current_entity = parent.0;
+                } else {
+                    break;
+                }
+            } else {
+                break;
+            }
+        }
+        if let Ok(mut node) = query_set.q1_mut().get_mut(entity) {
+            node.bounds = bounds;
+        }
+    }
+}
+
 #[allow(clippy::too_many_arguments)]
 pub fn flex_node_system(
     windows: Res<Windows>,
diff --git a/crates/bevy_ui/src/lib.rs b/crates/bevy_ui/src/lib.rs
index 352dba04f4972..8b7f40c2f9e52 100644
--- a/crates/bevy_ui/src/lib.rs
+++ b/crates/bevy_ui/src/lib.rs
@@ -58,6 +58,7 @@ impl Plugin for UiPlugin {
             .register_type::<Rect<Val>>()
             .register_type::<Style>()
             .register_type::<Val>()
+            .register_type::<Overflow>()
             .add_system_to_stage(
                 CoreStage::PreUpdate,
                 ui_focus_system.system().after(InputSystem),
@@ -78,6 +79,12 @@ impl Plugin for UiPlugin {
                     .label(UiSystem::Flex)
                     .before(TransformSystem::TransformPropagate),
             )
+            .add_system_to_stage(
+                CoreStage::PostUpdate,
+                bounds_node_system
+                    .system()
+                    .after(TransformSystem::TransformPropagate),
+            )
             .add_system_to_stage(
                 CoreStage::PostUpdate,
                 ui_z_system
diff --git a/crates/bevy_ui/src/render/ui.frag b/crates/bevy_ui/src/render/ui.frag
index 985f5006ed4d2..456fc7f6ab5c1 100644
--- a/crates/bevy_ui/src/render/ui.frag
+++ b/crates/bevy_ui/src/render/ui.frag
@@ -1,20 +1,25 @@
 #version 450
 
 layout(location = 0) in vec2 v_Uv;
-
+layout(location = 1) in vec4 v_Bounds;
 layout(location = 0) out vec4 o_Target;
 
 layout(set = 2, binding = 0) uniform ColorMaterial_color {
     vec4 Color;
 };
 
-# ifdef COLORMATERIAL_TEXTURE 
+# ifdef COLORMATERIAL_TEXTURE
 layout(set = 2, binding = 1) uniform texture2D ColorMaterial_texture;
 layout(set = 2, binding = 2) uniform sampler ColorMaterial_texture_sampler;
 # endif
 
 void main() {
-    vec4 color = Color;
+    if(gl_FragCoord.x <= v_Bounds.x || gl_FragCoord.x >= v_Bounds.z ||
+        gl_FragCoord.y <= v_Bounds.y || gl_FragCoord.y >= v_Bounds.w)
+    {
+        discard;
+    }
+vec4 color = Color;
 # ifdef COLORMATERIAL_TEXTURE
     color *= texture(
         sampler2D(ColorMaterial_texture, ColorMaterial_texture_sampler),
diff --git a/crates/bevy_ui/src/render/ui.vert b/crates/bevy_ui/src/render/ui.vert
index b1f1aff935af6..021130100564a 100644
--- a/crates/bevy_ui/src/render/ui.vert
+++ b/crates/bevy_ui/src/render/ui.vert
@@ -5,6 +5,7 @@ layout(location = 1) in vec3 Vertex_Normal;
 layout(location = 2) in vec2 Vertex_Uv;
 
 layout(location = 0) out vec2 v_Uv;
+layout(location = 1) out vec4 v_Bounds;
 
 layout(set = 0, binding = 0) uniform CameraViewProj {
     mat4 ViewProj;
@@ -17,8 +18,14 @@ layout(set = 1, binding = 1) uniform Node_size {
     vec2 NodeSize;
 };
 
+layout(set = 1, binding = 2) uniform Node_bounds {
+    vec4 Bounds;
+};
+
+
 void main() {
     v_Uv = Vertex_Uv;
+    v_Bounds = Bounds;
     vec3 position = Vertex_Position * vec3(NodeSize, 0.0);
     gl_Position = ViewProj * Object * vec4(position, 1.0);
 }
diff --git a/crates/bevy_ui/src/ui_node.rs b/crates/bevy_ui/src/ui_node.rs
index 576fb8833d468..537c0eefe4012 100644
--- a/crates/bevy_ui/src/ui_node.rs
+++ b/crates/bevy_ui/src/ui_node.rs
@@ -1,5 +1,5 @@
 use bevy_ecs::reflect::ReflectComponent;
-use bevy_math::{Rect, Size, Vec2};
+use bevy_math::{Rect, Size, Vec2, Vec4};
 use bevy_reflect::{Reflect, ReflectDeserialize};
 use bevy_render::renderer::RenderResources;
 use serde::{Deserialize, Serialize};
@@ -9,6 +9,7 @@ use std::ops::{Add, AddAssign};
 #[reflect(Component)]
 pub struct Node {
     pub size: Vec2,
+    pub bounds: Vec4,
 }
 
 #[derive(Copy, Clone, PartialEq, Debug, Serialize, Deserialize, Reflect)]
@@ -72,6 +73,7 @@ pub struct Style {
     pub min_size: Size<Val>,
     pub max_size: Size<Val>,
     pub aspect_ratio: Option<f32>,
+    pub overflow: Overflow,
 }
 
 impl Default for Style {
@@ -97,6 +99,7 @@ impl Default for Style {
             min_size: Size::new(Val::Auto, Val::Auto),
             max_size: Size::new(Val::Auto, Val::Auto),
             aspect_ratio: Default::default(),
+            overflow: Default::default(),
         }
     }
 }
@@ -251,6 +254,19 @@ impl Default for FlexWrap {
     }
 }
 
+#[derive(Copy, Clone, PartialEq, Debug, Serialize, Deserialize, Reflect)]
+#[reflect_value(PartialEq, Serialize, Deserialize)]
+pub enum Overflow {
+    Visible,
+    Hidden,
+}
+
+impl Default for Overflow {
+    fn default() -> Overflow {
+        Overflow::Visible
+    }
+}
+
 #[derive(Default, Copy, Clone, Debug)]
 pub struct CalculatedSize {
     pub size: Size,
diff --git a/examples/ui/ui.rs b/examples/ui/ui.rs
index 9ef72554ba1fe..a2ee102890554 100644
--- a/examples/ui/ui.rs
+++ b/examples/ui/ui.rs
@@ -124,6 +124,7 @@ fn setup(
                         .spawn_bundle(NodeBundle {
                             style: Style {
                                 size: Size::new(Val::Px(100.0), Val::Px(100.0)),
+                                overflow: Overflow::Hidden,
                                 ..Default::default()
                             },
                             material: materials.add(Color::rgb(1.0, 0.0, 0.0).into()),

From 3054b829cced8fe9bc8aee674383607687582c8b Mon Sep 17 00:00:00 2001
From: James Higgins <james.isaac.higgins@gmail.com>
Date: Sun, 18 Apr 2021 17:26:05 -0300
Subject: [PATCH 2/2] Add Overflow::Hidden to text nodes

---
 .../bevy_sprite/src/render/sprite_sheet.frag  |  5 +++++
 .../bevy_sprite/src/render/sprite_sheet.vert  |  3 +++
 crates/bevy_sprite/src/texture_atlas.rs       |  9 ++++++--
 crates/bevy_text/src/draw.rs                  |  4 +++-
 crates/bevy_text/src/text2d.rs                |  1 +
 crates/bevy_ui/src/widget/text.rs             |  1 +
 examples/ui/ui.rs                             | 22 +++++++++++++++++++
 7 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/crates/bevy_sprite/src/render/sprite_sheet.frag b/crates/bevy_sprite/src/render/sprite_sheet.frag
index 8c8d9217f08d1..f7a430946cb37 100644
--- a/crates/bevy_sprite/src/render/sprite_sheet.frag
+++ b/crates/bevy_sprite/src/render/sprite_sheet.frag
@@ -2,6 +2,7 @@
 
 layout(location = 0) in vec2 v_Uv;
 layout(location = 1) in vec4 v_Color;
+layout(location = 2) in vec4 v_Bounds;
 
 layout(location = 0) out vec4 o_Target;
 
@@ -9,6 +10,10 @@ layout(set = 1, binding = 2) uniform texture2D TextureAtlas_texture;
 layout(set = 1, binding = 3) uniform sampler TextureAtlas_texture_sampler;
 
 void main() {
+    if(gl_FragCoord.x >= v_Bounds.x || gl_FragCoord.x <= v_Bounds.z ||
+        gl_FragCoord.y >= v_Bounds.y || gl_FragCoord.y <= v_Bounds.w) {
+        discard;
+    }
     o_Target = v_Color * texture(
         sampler2D(TextureAtlas_texture, TextureAtlas_texture_sampler),
         v_Uv);
diff --git a/crates/bevy_sprite/src/render/sprite_sheet.vert b/crates/bevy_sprite/src/render/sprite_sheet.vert
index 62ecf3323785a..1bc5a8514c06f 100644
--- a/crates/bevy_sprite/src/render/sprite_sheet.vert
+++ b/crates/bevy_sprite/src/render/sprite_sheet.vert
@@ -6,6 +6,7 @@ layout(location = 2) in vec2 Vertex_Uv;
 
 layout(location = 0) out vec2 v_Uv;
 layout(location = 1) out vec4 v_Color;
+layout(location = 2) out vec4 v_Bounds;
 
 layout(set = 0, binding = 0) uniform CameraViewProj {
     mat4 ViewProj;
@@ -34,6 +35,7 @@ layout(set = 2, binding = 1) uniform TextureAtlasSprite {
     vec4 color;
     uint index;
     uint flip;
+    vec4 bounds;
 };
 
 void main() {
@@ -82,4 +84,5 @@ void main() {
 
     v_Color = color;
     gl_Position = ViewProj * SpriteTransform * vec4(vertex_position, 1.0);
+    v_Bounds = bounds;
 }
diff --git a/crates/bevy_sprite/src/texture_atlas.rs b/crates/bevy_sprite/src/texture_atlas.rs
index 76df36000f6bb..d0632d0618e02 100644
--- a/crates/bevy_sprite/src/texture_atlas.rs
+++ b/crates/bevy_sprite/src/texture_atlas.rs
@@ -1,7 +1,7 @@
 use crate::Rect;
 use bevy_asset::Handle;
 use bevy_core::Bytes;
-use bevy_math::Vec2;
+use bevy_math::{Vec2, Vec4};
 use bevy_reflect::TypeUuid;
 use bevy_render::{
     color::Color,
@@ -33,6 +33,7 @@ pub struct TextureAtlasSprite {
     pub index: u32,
     pub flip_x: bool,
     pub flip_y: bool,
+    pub bounds: Vec4,
 }
 
 impl RenderResource for TextureAtlasSprite {
@@ -50,7 +51,8 @@ impl RenderResource for TextureAtlasSprite {
         self.color.write_bytes(color_buf);
 
         // Write the index buffer
-        let (index_buf, flip_buf) = rest.split_at_mut(4);
+        let (index_buf, rest) = rest.split_at_mut(4);
+        let (flip_buf, bounds_buf) = rest.split_at_mut(4);
         self.index.write_bytes(index_buf);
 
         // First bit means flip x, second bit means flip y
@@ -58,6 +60,8 @@ impl RenderResource for TextureAtlasSprite {
         flip_buf[1] = 0;
         flip_buf[2] = 0;
         flip_buf[3] = 0;
+
+        self.bounds.write_bytes(bounds_buf);
     }
 
     fn texture(&self) -> Option<&Handle<Texture>> {
@@ -72,6 +76,7 @@ impl Default for TextureAtlasSprite {
             color: Color::WHITE,
             flip_x: false,
             flip_y: false,
+            bounds: Default::default(),
         }
     }
 }
diff --git a/crates/bevy_text/src/draw.rs b/crates/bevy_text/src/draw.rs
index 9e26a456b5207..749d738f6d6a1 100644
--- a/crates/bevy_text/src/draw.rs
+++ b/crates/bevy_text/src/draw.rs
@@ -1,4 +1,4 @@
-use bevy_math::{Mat4, Vec3};
+use bevy_math::{Mat4, Vec3, Vec4};
 use bevy_render::{
     draw::{Draw, DrawContext, DrawError, Drawable},
     mesh,
@@ -21,6 +21,7 @@ pub struct DrawableText<'a> {
     pub text_glyphs: &'a Vec<PositionedGlyph>,
     pub msaa: &'a Msaa,
     pub font_quad_vertex_layout: &'a VertexBufferLayout,
+    pub bounds: Vec4,
 }
 
 impl<'a> Drawable for DrawableText<'a> {
@@ -74,6 +75,7 @@ impl<'a> Drawable for DrawableText<'a> {
                 color: self.sections[tv.section_index].style.color,
                 flip_x: false,
                 flip_y: false,
+                bounds: self.bounds,
             };
 
             // To get the rendering right for non-one scaling factors, we need
diff --git a/crates/bevy_text/src/text2d.rs b/crates/bevy_text/src/text2d.rs
index 112ce1cac0c11..1d51138826514 100644
--- a/crates/bevy_text/src/text2d.rs
+++ b/crates/bevy_text/src/text2d.rs
@@ -112,6 +112,7 @@ pub fn draw_text2d_system(
                 font_quad_vertex_layout: &font_quad_vertex_layout,
                 scale_factor,
                 sections: &text.sections,
+                bounds: Default::default(),
             };
 
             drawable_text.draw(&mut draw, &mut context).unwrap();
diff --git a/crates/bevy_ui/src/widget/text.rs b/crates/bevy_ui/src/widget/text.rs
index a8dce7ea1a191..22e2012aa643f 100644
--- a/crates/bevy_ui/src/widget/text.rs
+++ b/crates/bevy_ui/src/widget/text.rs
@@ -177,6 +177,7 @@ pub fn draw_text_system(
                 text_glyphs: &text_glyphs.glyphs,
                 font_quad_vertex_layout: &vertex_buffer_layout,
                 sections: &text.sections,
+                bounds: node.bounds,
             };
 
             drawable_text.draw(&mut draw, &mut context).unwrap();
diff --git a/examples/ui/ui.rs b/examples/ui/ui.rs
index a2ee102890554..3c3080f52f2cf 100644
--- a/examples/ui/ui.rs
+++ b/examples/ui/ui.rs
@@ -131,6 +131,28 @@ fn setup(
                             ..Default::default()
                         })
                         .with_children(|parent| {
+                            parent.spawn_bundle(TextBundle {
+                                style: Style {
+                                    margin: Rect::all(Val::Px(5.0)),
+                                    position_type: PositionType::Absolute,
+                                    position: Rect {
+                                        left: Val::Px(20.0),
+                                        bottom: Val::Px(-20.0),
+                                        ..Default::default()
+                                    },
+                                    ..Default::default()
+                                },
+                                text: Text::with_section(
+                                    "Text Example",
+                                    TextStyle {
+                                        font: asset_server.load("fonts/FiraSans-Bold.ttf"),
+                                        font_size: 30.0,
+                                        color: Color::WHITE,
+                                    },
+                                    Default::default(),
+                                ),
+                                ..Default::default()
+                            });
                             parent.spawn_bundle(NodeBundle {
                                 style: Style {
                                     size: Size::new(Val::Px(100.0), Val::Px(100.0)),